With a Main Array in Hibernation, What's Next for SETI?

This April, after only three and a half years of listening for life beyond our planet, the Allen Telescope Array suddenly closed its ears. The array, a collection of 42 radio telescopes in northern California, had to go into hibernation mode after money from the National Science Foundation and the state of California dried up. Allen can't be used to collect data but is being maintained by a reduced staff, says Seth Shostak, a senior astronomer with the Mountain View, Calif.-based SETI Institute, which runs the observatory along with the University of California, Berkeley. (SETI, which stands for "search for extraterrestrial intelligence," is also the name for the entire field and not just the institute.) "It's changed our job description from collecting data using the array to finding resources to put it back on the air," Shostak says.
Jill Tarter, director of the group's Center for SETI Research, says that the program is working to get Allen back online through small donations from individuals–a project called "SETIStars." As of late July, she says, the program has progressed more than halfway toward its fundraising goal of $200,000 to get the array up and running in August, albeit temporarily.But while the Allen Array hibernates, the number of promising places to look for alien life expands almost daily. For example, the Kepler Space Observatory has identified more than 1200 potential planets orbiting stars within the Milky Way that lay within the "habitable zone," where scientists calculate liquid water could exist–and possibly life too. Thankfully, SETI's budget woes don't mean that its scientists aren't looking and listening: A host of different creative projects around the world keep the search for intelligent aliens going.

Array Closed Down

Array Closed Down

This April, after only three and a half years of listening for life beyond our planet, the Allen Telescope Array suddenly closed its ears. The array, a collection of 42 radio telescopes in northern California, had to go into hibernation mode after money from the National Science Foundation and the state of California dried up. Allen can't be used to collect data but is being maintained by a reduced staff, says Seth Shostak, a senior astronomer with the Mountain View, Calif.-based SETI Institute, which runs the observatory along with the University of California, Berkeley. (SETI, which stands for "search for extraterrestrial intelligence," is also the name for the entire field and not just the institute.) "It's changed our job description from collecting data using the array to finding resources to put it back on the air," Shostak says.

Jill Tarter, director of the group's Center for SETI Research, says that the program is working to get Allen back online through small donations from individuals–a project called "SETIStars." As of late July, she says, the program has progressed more than halfway toward its fundraising goal of $200,000 to get the array up and running in August, albeit temporarily.

But while the Allen Array hibernates, the number of promising places to look for alien life expands almost daily. For example, the Kepler Space Observatory has identified more than 1200 potential planets orbiting stars within the Milky Way that lay within the "habitable zone," where scientists calculate liquid water could exist–and possibly life too. Thankfully, SETI's budget woes don't mean that its scientists aren't looking and listening: A host of different creative projects around the world keep the search for intelligent aliens going.

Many Ways To Listen

Many Ways To Listen

UC Berkeley astronomer Dan Werthimer leads SETI projects at five different telescopes around the world; his primary work happens at the Arecibo Observatory in Puerto Rico, the world's largest single-dish radio telescope. (Radio telescopes function as giant concave mirrors for radio waves, their dish-like shape focusing beams toward a single point, where a receiver detects and records them.) Werthimer's group has an arrangement with Arecibo to "piggyback" onto all other astronomer's projects, searching for radio signals emanating from wherever in the heavens the observatory is pointed. So though Werthimer and his team don't aim the telescope, they siphon off its data 24 hours a day.

Some of the data is analyzed on-site, but much of it is sent out to the volunteers of the SETI@Home program, a network of 8 million people who have downloaded Werthimer's computer program over the last decade. By tapping into the volunteers' computing power as their machines idle, Werthimer has created a supercomputer-like conglomeration to search for unusual patterns that could be of alien origin.

At the Green Bank telescope in West Virginia (the world's largest steerable telescope), Werthimer's doctoral student Andrew Siemion is listening, too. He's now sorting through his team's first round of observations, during which they pointed Green Bank's 330-foot dish at 90 planets the Kepler mission has picked out as having earth-like orbits around sun-like stars. Seimion just transferred 40 terabytes of data from the project–enough to fill more than 5000 DVDs–back to Berkeley and has begun analyzing it for possible alien signatures.

Green Bank was home to the first-ever SETI search, by Frank Drake, developer of the famous Drake equation that estimates the number of detectable civilizations in the Milky Way (He's still working, too–helping the SETI Institute in its attempt to secure addition funding from the Department of Defense, he tells PM). But where Drake's 1961 experiment with a vacuum-tube receiver searched for transmissions on a single channel, nowadays Werthimer and Siemion can monitor 10 billion radio wavelengths at the same time. "It's like listening to 10 billion radios at once," Werthimer says.

Larger telescopes such as Green Bank and Arecibo can detect more signals and fainter or more distant ones. But large telescopes are in high demand and cannot usually be quickly pointed toward a promising signal. To get around this problem, alien-hunters combined forces. A worldwide group of 1500 small-antenna operators called the SETI League now scans the whole sky. The group's leader, Paul Shuch, says that what their network lacks in sensitivity it makes up for in responsiveness and verifiability. If any of the 150 telescopes actively searching at any given time spot something weird, others in the group automatically receive an email telling them to check it out.